Air booster steering



N 1953 H. c. SQHINDLER 60,255

AIR BOOSTER STEERING Filed Feb. 16, 1950 3 Sheets-Sheet 1 INVENTOR. HAROLD C. SCHINDLER ATTORNEYS N 1953 H. c. SCHINDLER AIR BOOSTER STEERING 3 Sheets-Sheet 2 Filed Feb. 16, 1950 9 0: 1 To: fl Nb vb wdv w & mm mm 2 mm on mm 5 m INVENTOR.

' HAROLD C. SCHINDLER ATTORNEYS H. C. SCHINDLER AIR BOOSTER STEERING Nov 24, 1953 5 Sheets-Sheet 3 Filed Feb. 16, 1950 INVENT OR. HAROLD C. SCHINDLER BY 7%7%%#flm ATTORNEYS Patented Nov. 24, 1953 AIR BOOSTER STEERING Harold C. Schindler, Euclid, Ohio, assignor to The Euclid Road Machinery 00., Euclid, Ohio,

a corporation of Ohio Application February 16, 1950, Serial N 0. 144,446

9 Claims. (01. 180-792) This invention relates to improvements in booster steering apparatus and more particularly to one which utilizes a compressible fluid such as air.

One of the objects of the present invention is to provide a novel booster steering apparatus which utilizes air or similar compressible fluid in such a manner that there is a resilience in the steering apparatus which permits the driver to retain the feel of the road, the vehicle is easily steered on rough ground, and under conditions which call for very little manual effort, the vehicle may be manually steered, resulting in a saving of compressed air.

1 Other objects and advantages of the present invention will be apparent from the accompanying drawings and description and the essential features will be set forth in the appended claims.

In the drawings,

Fig. 1 is a side elevational view of one type of vehicle equipped with my improved booster steering apparatus;

Fig. 2 is a fragmental end elevational view somewhat enlarged of the booster steering apparatus of Fig. 1, this view being taken from the position of the line 22 of Fig. 1, together with a diagrammatic showing of other compressed air connections;

Fig. 3 is a fragmental sectional View of the connection between the pitman arm and the steering apparatus, this view being taken along the line 3--3 of Fig. and also along the line 3-3 of Fig. 1, being an enlargement of Fig. 1

Fig. 4 is a transverse sectional view taken along the line 4-4 of Fig. 3; v r Fig. 5 is a central sectional view greatly enlarged through the left hand end of the booster steering apparatus as shown in Fig. 1;

Figs. 6 and 7 are views of the valve portion of Fig. 5 showing different positions'of the valves; Fig. 8 is a transverse sectional view taken along the line 88 of Fig. 5; while Fig. 9 is a transverse sectional view taken along the line 99 of Fig. 5.

Booster steering devices are old. Many of them, however, are operated by hydraulic fluid disadvantages in the practical operation of steering a vehicle. The present invention utilizes a compressible fluid such as compressed air. An

advantage of this system is that the average vehicle supplied with compressed air for operating air brakes, need nothave an additional power system but may use the compressed air for operating my improved booster steering apparatus.

which is incompressible and which leads to many Different constructions might be used with various types of vehicles. I have chosen to illustrate my invention as applied to a representative type of tractor having a frame ll mounted on wheels 12 and driven by an engine under the hood l3. This vehicle is intended to represent any heavy vehicle either of the highway type or of the off-the-highway type. It may also represent a tractor having a hitch connection with a heavier vehicle such as an earth digging scraper or dump wagon or the like. This representative vehicle is steered by means of the wheel [4 which is connected with a steering column E5, the bottom of which is connected by means, not shown, with a pitman arm 16 which in turn is connected, by means of a ball stud Ilia, with the housing I! of the booster steering apparatus. This housing, in turn, is connected by means of ball stud I8 with drag link 19 which in turn is connected to the steering arms for steering the front wheels [2.

Referring now to Fig. 5, the ball stud Ita is mounted in a sleeve 20 which is slidable in the interior diameter of the housing ll. Bearing blocks 2| within the sleeve are held in place between the shoulder 20a at one end of the sleeve and a closing cap 22 at the opposite end of the sleeve which has a threaded connection with the interior wall of the sleeve. A spring 23 maintains a snug grip between the bearing blocks and the ball stud IBa. A look ring 24 prevents the cap 22 from backing off. Integral with the cap 22, is a valve actuating rod 25, to the outer end of which a yoke 26 isfixed by means of a nut 27. The rod 25 passes through annular plates 28 and 29. A strong spring 30 presses plate 28 against the shoulder 22a of the cap 22 and presses plate 29 against the yoke 26. Plate 28 cannot move beyond stop 2! and'plate 29 cannot move beyond stop 32. It results from this construction, that the pitman arm 16 may be moved to carry the ball stud 16a slightly to the left or to the right as shown in Fig. 5, carrying with it the sleeve 20, the cap 22, the rod 25 and the yoke 26. Movement in either direction will compress the spring 30, which will then tend to again center the ball stud Ilia at its neutral point.

This lead movement of the ball stud 16a results in the operation of the air valves to actuate the booster apparatus as will presently appear.

The power for steering is provided by cylinder ted into the steering circuit.

whichever element moves and I intend to cover both forms of my device, although for simplicity in description and claiming, the piston 34 will be referred to as fixed and the cylinder 33 as movable. I intend by this language, however, to cover a reversal of parts. For this purpose, the piston a l has a piston rod as, which asses out of the right hand end of cylinder 33 through suitable packing and a boot 36. The piston rod has a ball and socket connection at 31 with "a bracket 38 which in turn is secured to the frame II. The left hand end of the cylinder 33, as shown in Fig. 5, is closed by meansoi a eyiinuer head casting 39 which is seemed by bolts 39-61, Fig. 8, which are threaded into ring 40 which is secured by lock ring 4| in theinterior wall it! the cylinder 33. A ring 412 holds the housing I! rigidly on the casting 39 as shown in 5.

v Within the casting 39 are provided air valves 13 and "M for controlling the new of compressed "air against the oppo ite races respectively of is 34, together with suitable suppl and exliaust passagewa s. The pressure fluid supply "passageway '45 leads at use to valve 43-, and at "4% valve to. Thispassageway is conne ted another passageway 16 (Fig. 8) leading oilitwai dly to communicate with "a pipe 41, also shown in Fig. which leads to the iar-end the cylinder where it is "connected by a flexible eonnection to a source compressed air carrid on the vehicle. The pressure 'iiuid'exhauoi passageway 48 has a connection at '48s for valve '41 and atltb for valve 43. This passageway is connected with atmosphere atti) through a filter '50 as shown -in Fig. '9. Supply and exhaust the near end of cylinder 33 is-by way "of power fluid supply and exhaust passageway 51. sup-- ply and exhaust to the 'far end of the cylinder is by way of power fluid supply and exhaust passageway 52, tube 53 running "along outside 'the cylinder wall and a passageway 54 at the other end'of the eylinder leadirig to the interior "of cylinder .3 3.

Notein :Fig. -2 a compressed air source 81 coir- *hected by line 32 to pipe 41 and by line 33 with So. brake system for "operating brake actuators .84, which are connected by means (not shown) toibrakes for wheels :12. lno'rd'er to make sure that the air brakes always have adequate pressure, and that the booster "steering device does not lower this pressure below a predetermhred point, ;a pressure regulator or r-elief valve =85 ;is;;installed in the line leading to the booster steering apparatus. 'In this way, when the :air .pressure drops below a predetermined point, say seventy .pounds, then no -more-air isadmit In this case, "of *course, the steering would have to be entirely manual. Under such conditions, with airshut ofi to the supply passageway 45, -movement of the steering apparatus might iprovidea suction in the passageway. A check -valve;55 is provided, as shown in Fig. 9, to prevent such a vacuum condition. Undersu ch conditions, the check valve =55 would be raised from its seat gagainst "the action of the light spring 56 to prevent the limilding up of e. vacuum in the'booster steering apparatus.

1 The; mechanism for controlling and operating the valves 43 and 44 are alike and therefore one only will be described. The valve 43 is -controlled by push rod '51. The end 'of this rod reill position. The flow of compressed air from sup ply passage a to the valve 43 is by means of a central passageway 60 in the push rod and a cross passageway 6|. Annular resilient seals 62 prevent leakage along the sides of the push rod. A seat is provided at 63 for the valve head 43a.- lA seat is provided in plate '63 for the valve head 33b. This seat plate is held in position by the packing nut 65 which holds rings of resilient packing 66 in position. Openings 6? are providedtlrrough the walls of the hollow nut 85 for the flow of air. A spring 68 presses against a hearing ring '69 to urge push rod 51 against yoke 26 at times. A tapered helical spring lob'ears against'the valve head 43a to urge the valve 43 at all times toward the left as viewed in Fig. 5. Because there is the pressure of air supply ihthe' passageway 60 against the valve head 43a, an additional helical spring is provided at I pressing against the valve '43 to urge the same toward the left and to withstand the unbalanced pressure of the supply fluid. Similar parts are provided in connection with valve 44. Those needing ntention here are "the push rod 12 with its adjustable stud 13 the flow passageway M for'exhaust'air, the valve seats 15 and I6, and springs H and 18-. No spring corresponding to H is needed, because the supply pressure against the valve head 14a always tends to move that valve to closed position.

The "operation of this form of my device should now be apparent. If the :pitman arm #6 is moved by the steering wheel M so as to carry the ball stud 16a toward the right as viewed in -F-ig-. 5-, then the yoke -26wi1l-be moved toward the right, compressing spring -30 slightly. This will move the push rods 51 and 1.2 to the positions shown in Fig. 6. Push rod 12 moves against the valve head 44b and pushes the valve head 44a to open position. Pressure fluid then flows from supply passageway 45b through open valve -Mu, through passageway 52 and through tube 53 to the right hand end of the booster cylinder. Since the piston rod 35 and piston 34 are arrohored, the cylinder 33 moves to the right until the valve 44a -is again seated in the position of Fig. 5 at which time the sleeve 20 and the ball stud 16a are again centered. At the same time tl-iis was occurring-the push rod-51 had moved the already slightly open exhaust valve 431) :further toward open position so that fluid exhaustecl from the left hand end of cylinder 33 might flow through passageway 5|,past valve head'43b and out through the-exhaust passageway 48?). M If thepitman arm J6 is moved toward the left, then ballstud [6a and sleeve 20 are carried toward the left as viewed in Fig. 5 until the parts assume the position shown in Fig. 7. The .yoke 26 then n oves toward the left and the push rods 51 and |2 follow toward the left impelled by springs 68 and H respectively. The'push rod 12 moves further away from the valve head Mb so as to give a, wide open exhaust through passageway -'U l and passageway 43a. This permits exhaust from the right hand end of cylinder '33 through tube :53, passageway 52 and valve Mb. Thepush rod -5jl-moves toward the left away from the valve head 43a. This permits the exhaust valve 43?) to close against its seat impelled by the springs -10 and H. The'movement of the pushrod 5''! toward the left fully opens the passageway 60 so that pressure fluid coming from the passageway 4 5a may now past the valve 43a and through passageway 51 to the left hand end of cylinder 33. This causes cylinder 33% move toward the left until sleeve 20 and ball stud [6a are again centered. Since the housing I! is con-, nected through the ball stud l8 with the drag link and steering apparatus, the air booster apparatus is effective in causing the steering apparatus to follow the movement of the steering wheel [4.

It has been noted that in the centered position of ball stud [6a and sleeve 20, the exhaust valves 43b and 441) are slightly raised from their respective valve seats. This permits manual operation below the booster range, that is, when the effort applied to the steering wheel I4 is insufiicient to compress the spring 30.

Note the space at 80, Fig. 5, permitting sleeve 20 to move toward the left to place the valve actuating parts in the position of Fig. 7.

In Figs. 3 and 4, I have shown a shoe 86 embracing the stem b of the ball stud Ilia. This shoe has parallel top and bottom surfaces 86a which slidingly engage an elongated slot Ila in the housing I1. Lost motion is provided in the slot so that booster steering may occur. This shoe prevents rotation of the booster about its own axis due to an off-center load, as from a bent drag link, and thus prevents possible resulting damage to ball studs and housings.

What I claim is:

1. In booster steering apparatus including an operator operated driving steering arm and a driven steering member and including a power device having fixed and movable members and first and second opposed expansible chambers for actuating said movable member substantially in a line and in opposite directions, the combination of a housing movable with said movable member, said housing connected with said driven steering member, a valve actuator reciprocable in said housing generally along said line, said actuator operatively connected with said steering arm, means biasing said actuator toward a centered position, two sets of valves, each set including an exhaust and a supply valve rigidly connected a fixed distance apart, a push rod for each of said valve sets, said push rods operatively connected with said actuator, valve seats for said exhaust and supply valves, one of said seats for each set being fixed and the other seat being movable with its associated push rod, the valves of a set closing in the same direction, means biasing said valves toward closed position, there being pressure fluid supply and exhaust passageways communicating with said valve seats and controllable by said associated valves, there being a power fiuid supply and exhaust passageway leading from a point intermediate the valve seats of one set to said first expansible chamber, there being a power fluid supply and exhaust passage- Way leading from a point intermediate the valve seats of the other set to said second expansible chamber, said actuator and push rods and valves and seats being so arranged that in one position said push rods bring said seats of each set nearer than said fixed distance whereby to close a supply valve and open an exhaust valve of each set and so arranged that in another position said push rods cause movement of said seats of each set farther apart than said fixed distance whereby to open a supply valve and close an exhaust valve of each set, and said valves and seats and passageways and push rods being so arranged that an open supply valve of one set communicates with one of said expansible chambers when the open exhaust valve of the other set communicates with the other of said expansible chambers.

2. The combination of claim 1 wherein the spacing of said valve seats when said actuator is in centered position is so arranged that the exhaust valve of each set is slightly open, whereby manual operation of said arm and actuator is possible without use of pressure fluid.

' 3. The combination of claim 1 wherein said pressure fiuid supply passageways communicate with a source of compressed air.

4. The combination of claim 1 wherein said valves and associated push rod of each set are reciprocable parallel to the line of actuation of said movable member of said power device, and a yoke connecting said actuator and said push rods.

5. The combination of claim 1, wherein each of said valve sets is of dumbell form with the supply valve of one set and the exhaust valve of the other set adjacent the push-rod-carried valve seats, the pressure fiuid supply passageway of said one set and the exhaust passageway of said other set extending through the associated push rod, and additional biasing means urging said supply valve of said one set toward its seat for overcoming the pressure of said fluid supply on said supply valve of said one set. I

6. Ihe combination of claiml, whereineach of said valve sets is of dumbell form, said pressure fluid supply and exhaust passageways being located beyond the ends of said dumbell Valves, and said power fluid supply and exhaust passageway of each set being located between the ends of said dumbell valve.

'7. In a vehicle, an air booster steering apparatus, an air operated braking apparatus, a common source of compressed air connected separately to each of said apparatus, a regulator valve between said source and said booster steering apparatus adapted to shut off the supply of air to said steering apparatus below a predetermined pressure, said steering apparatus including an operator-operated steering arm and vehicle steering connections for steering said vehicle manually, said steering arm connections including a part having limited lost motion, a booster steering cylinder-and-piston motor having a movable member connected with said steering arm, air supply and exhaust passageways communicating between said cylinder of said motor and said compressed air source, valve means in said passageways operatively associated with said lost motion part and operable in one direction by steering arm motion to connect said supply passageway to one end of said cylinder and to connect said exhaust passageway to the other end of said cylinder, and means operable by resultant motion of said movable member to return said valve means in the opposite direction to neutral or non-supply position, whereby when said source is above a predetermined pressure said steering motor may operate, but when said source is below a predetermined pressure, said regulator valve is closed, steering must be manual, and air is conserved for said other braking apparatus.

8. The combination of claim '7 including a check valve communicating between atmosphere and said supply passageway, and said check valve opening into said supply passageway only, whereby if no air is available in said supply passageway and relative movement between the cylinder and piston of said motor causes a partial vacuum in said supply passageway, said check valve will open.

9. In a vehicle having air booster steering apparatus and a source of compressed air for operat 7 Sing said apparatus, said steering apparatus-including an operator-operated steering arm vehicle steering connections tor steering said vehicle manually, said steering arm connections incl-riding a part having limited -lost motion, :a booster steering -cyiliinder--and-:pis'ton motor has/:- ing a movable member connected :saiidrstcering arm, air-supply and exhaust passageways com: municating between said cylinder of said motor and said compressed air sour-ice, val-me means in :said passageways .operatioely associated with said :lost motion part and operable one direction by steering arm motion :to connect .said .slipply pas .sageway 110 one end of said cylinder and to iconnect said exhaust passageway to the other end .of said cylinder, and there bemgasififi spring prowiding an essential operating connection between said name :means and said ilost motion pant, whereby said steering apparatus is operated mannalzly said manual vefilont fiufiicienlt to onercome said .stifi tearing and openate said hooster steering apparatus, :and thereby air :for open-.- a'ting said booster steering apparatus is con.- seiwed, .a housing movablewith-the fixed member of said motor, there being a slotted opening in said housing providing parallel ways extending parallel to the direction of movement of said lost 8 motion part, astud conneetedhetween said steer ing arni and said lost motion part and entering said housing through said opening and having a and socket connection izvithin said housing, and a shoe embracing said stud and having par.- a l lei surfaces siidingiy engaging said ways of .said slotted opening whereby rotation of the booster about its own axis due to an off center ioad is prevented by said sliding shoe.

- C. SCHINDIiER.

fleferences G te in the 1 1 s o in en UNITED STATES 'PA'I'ENTS Number N me Dat lifibfi z i Bragg et a1. -w-t-.. s Aug. .15, 11 2? 1,647,404 Gehrig 4 Nov. 1, 1927 13 6, 1 Davis l. l -,-v-. -.-V-H- 23 19 2363,9757 Kosher i.-. .Nov. 2.81, i944 2,361,115 Qoepirich ,Jan- 9,, .1945 2,36 i Bowlin Eeb- 1 95 '2,45Q,125 Fish ry-a1 ent. 12.8, .958 M81613 'Twyman L r 4 .Nov. 8, 9

LEQREIGN PATENTS "Number Gounbry Date 104,246 France May 15, 1935. 

